1. Field of the Invention
The present invention relates to miniature heat dissipating fan assemblies, and more particularly to miniature heat dissipating fan assemblies each having a balance plate for assuring stable rotational movement of the rotor axle.
2. Description of the Related Art
Taiwan Utility Model Patent Publication No. 316733 issued on Sep. 3, 1997, corresponding to U.S. Pat. No. 5,699,854, discloses a miniature heat dissipating fan assembly for outputting air in a certain direction. The fan assembly includes a base plate having a compartment with a helical channel and an air outlet. A tube seat is mounted in the compartment and includes an axle hole for rotatably receiving an axle tube of a coil seat. A coil on the coil seat generates magnetic fields to drive the fan to rotate. The fan includes a number of blades for sucking air into the fan assembly and outputting air via the outlet. A cover plate is provided to the base plate and includes an air inlet having a diameter smaller than that of the fan. The base plate includes a number of engaging notches, while the cover plate includes a number of corresponding inverted hooks for securely engaging with the engaging notches. Such miniature fan assembly has a relatively small thickness such that only one bearing can be used in the axle tube. As a result, the axle of the fan mounted in the axle tube tends to vibrate and/or slant. The present invention is intended to provide improved miniature fan assemblies to solve this problem.